Synthetic bowling pins



United States Patent ()fiice 3,147,074 Patented Sept. 8, 1964 3,147,974SYNTHETIC BOWLING PINS Leandra W. Tomarkin, Spring Valley, N.Y.,assignor, by mesne assignments, to American Machine & Foundry Company, acorporation of New Jersey No Drawing. Filed Nov. 12, 1959, Ser. No.852,210 6 Claims. (Cl. 273-32) This invention relates to bowling pins,and more particularly, concerns pins formed of synthetic, non-cellulosicorganic material.

Conventional bowling pins are formed of sound, hard maple, in a singlepiece or in laminated form. As the pins must meet rigid specifications,the wood must be well selected, properly seasoned, and otherwise be ofhigh quality, to allow the same to be fabricated into commerciallyacceptable pins.

As bowling becomes progressively more popular, with ever increasing pinrequirements; the limited supply of satisfactory maple for pinmanufacture, has given rise to substantial problems in the industry.

Furthermore, wood pins have a rather limited useful life due to abrasionand indentation in use. The normal deterioration of wood pins has beenaggravated by the common usage of mechanical pin spotters, which imposea further wear on the pins as they are handled by the mechanism. After arelatively short interval of use, wood pins must be discarded orrehabilitated. Rehabilitation usually comprises shaving the pin toremove abraded or indented surface portions, followed by the applicationof various surfacing compositions or lacquers.

The use of a coating composition on the pins makes the pin bodynon-homogeneous, particularly with a substantial difference in specificgravity as between the coating composition and the wood, leading to animpairment in the qualities of the rehabilitated pin. Thus, the pin maybe somewhat unbalanced; it does not have the bounce of the original pin;it does not emit the same sound on impact by the ball, and otherwiseconstitutes a somewhat inferior product, as compared to the original,all wood pin.

While attempts have been made to manufacture bowling pins fromnon-cellulosic materials, such efforts have met with little success.This is due to the large number of diverse properties andcharacteristics which must be exhibited by the finished pin, to meetrigid specifications and the preferences of bowlers. Thus, the specificgravity of the material from which the pin is made must be rigidly heldwithin the range of .70 to .60, preferably .60. Furthermore, thematerial must have high abrasion resistance and a degree of resiliencywhich avoids permanent indentations on the pin surface.

In addition, the pin must show the correct amount of bounce when hit andmust produce a sound when struck by the ball which is quite similar withthat associated with struck wood pins. Furthermore, the pin must be madeof a material which can be held to strict tolerances in respect todimensions, specific gravity, and resistance to effects of humidity andtemperature changes during normal usage.

In accordance with the instant invention, it has been found that asynthetic elastomericvmaterial known as polyurethane, can be fabricatedinto the form of bowling pins which show the several properties andcharacteristics mandatory in a commercially acceptable bowling pin.

The polyurethane, which is an organic diisocyanate modified polyether orpolyester, is molded into a rigid body taking the form of a bowling pin.The polyurethane composition is formulated in liquid form and isintroduced into an appropriate mold in a precisely measured amount. Theformulation is of the type which foams to produce a cellular structure;which structure is adapted to have a predetermined specific gravity.Furthermore, the cells of the resultant molded body are preferably ofthe sealed, non-communicating type. The cells may have an averagediameter of from about 0.5 to about 1.5 mm.

The foaming of the polyurethane composition within the mold is inducedby the use of additional diisocyanate and water in the formulation; orby the use of foaming agents added to the composition, such as thehalogenated hydrocarbons known as Freon, or the like. In this manner,the extent and distribution of the cells may be carefully controlled, toproduce a finished molded pin having the desired specific gravity ofabout .60.

The molds are precisely dimensioned to insure accurate dimensioning ofthe finished molded pin, in accordance with accepted specifications. Thefoamable polyurethane composition is homogeneous throughout, and may, ifdesired, include an inert, inorganic filler in finely powdered formwhich is uniformly distributed through the composition. The filler mayinclude titanium dioxide, magnesium oxide, aluminum trisilicate, or thelike, in amounts of from about 5% to about 15% by weight. The filler mayimpart a uniform, homogeneous color to the molded pin body.

The polyurethane composition is made up with the requisite catalysts andother ingredients necessary to produce a foamed end product of the rigidtype. The composition is measured out for introduction into the molds,in amounts suificient to allow for the desired extent of foaming action.

It has been found that the resultant, molded rigid pin bodies are highlyresistant to abrasion and wear incident to the impact of the balls andhandling by the mechanical pin spotters. Furthermore, the novel pinsshow excellent bounce characteristics entirely analogous to thosenormally associated with wood pins. Also, the polyurethane bowling pinsproduce a sound on impact by the balls, which is quite similar to thatencountered with wood pins.

The molded polyurethane bowling pins show uniform balance and response,despite wide changes in humidity and varying temperatures within thelimit of normal usage. Also, the pins can be produced in large numberswith small variations in weight as between individual pins; thus makingpossible closer weight tolerances than is possible with the wood pins.

The molded pins are readily cleaned with various commercially availabledetergents or solvents, which are without effect on the material fromwhich the pin is made. With selected fillers, the molded pin will have auniform, integral color. Thus, titanium dioxide will impart a whitecolor to the pins.

As various changes might be made in the embodiments of the inventionherein disclosed without departing from the spirit thereof, it isunderstood that all matter herein set forth is illustrative and notlimiting except as set forth in the appended claims.

Having thus disclosed my invention, I claim as new and desire to protectby Letters Patent:

1. A bowling pin consisting of a rigid, homogeneous body of polyurethanehaving a cellular structure, the cells in said body having a size offrom about 0.05 to about 1.50 mm. in diameter, said body being elongatedand comprising a base at one end for engaging a playing surface, and aportion between said base and the other end adapted to be struck by aball rolling along such playing surface.

2. A bowling pin consisting of a rigid molded homogeneous body ofpolyurethane having a cellular structure, the cells of said structurebeing of substantially uniform size not exceeding about 1.5 mm. indiameter, said body being elongated and comprising a base at one end forengaging a playing surface, and a portion between said 3 base and theother end adapted to be struck by a ball rolling along such playingsurface.

3. A bowling pin consisting of a rigid, homogeneous body of cellularpolyurethane, said body being colored white by the inclusion in saidbody of finely powdered titanium dioxide in an amount not exceeding 15%by weight, said body being elongated and comprising a base at one endfor engaging a playing surface, and a portion between said base and theother end adapted to be struck by a ball rolling along such playingsurface.

4. A bowling pin consisting of a rigid body of polyurethane having acellular structure, said body being elongated and comprising a base atone end for engaging a playing surface, and a portion between said baseand the other end adapted to be struck by a ball rolling along suchplaying surface.

5. A bowling pin consisting of a rigid body of polyurethane having acellular structure and wherein the cells of said body are sealed and innon-communicating 20 portion between said base and the other end adaptedto be struck by a ball rolling along such playing surface.

6. A bowling pin consisting of a rigid body of a reaction product of apolyether and an organic diisocyanate, said body having a cellularstructure, said body being elongated and comprising a base at one endfor engaging a playing surface, and a portion between said base and theother end adapted to be struck by a ball rolling along such playingsurface.

References Cited in the file of this patent UNITED STATES PATENTS2,866,774 Price Dec. 30, 1958 2,894,919 Simon et al. July 14, 19593,012,987 Ansul Dec. 12, 1961 3,015,132 Bunting Jan. 2, 1962 FOREIGNPATENTS 733,624 Great Britain July 13, 1955 OTHER REFERENCES RubberWorld for March, 1955; pages 765-769 cited.

ERNEST W. SWIDER Aottesting Officer UNITED. STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No. 3, 147,974 September S 1964 LeandroW Tomarkin It is hereby certified that error appears in the abovenumbered patent requiring correction and the,

t the said Letters Patent should read as corrected be1o* Column 2, line5, for "O.5' read .05

Signed and sealed this 12th day of January 1965.,

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of 5 Patents

4. A BOWLING PIN CONSISTING OF A RIGID BODY OF POLYURETHANE HAVING ACELLULAR STRUCTURE, SAID BODY BEING ELONGATED AND COMPRISING A BASE ATONE END FOR ENGAGING A PLAYING SURFACE, AND A PORTION BETWEEN SAID BASEAND THE OTHER END ADAPTED TO BE STRUCK BY A BALL ROLLING ALONG SUCHPLAYING SURFACE.